Figure 1: Evidence of possible asymptomatic BV infections in Asia. (a) Sera from individuals working at monkey forests in SE Asia [19, 20] were tested by ELISA as described [21, 22] against HSV1 (dark blue), HSV2 (light blue), BV (red), HVP2 (orange), squirrel monkey herpesvirus (light green), and spider monkey herpesvirus (dark green) antigens. HSV1 OD values were normalized to 1.0 to assess relative levels of reactivity with cross-reactive antigens. Average levels of cross-reactivity with BV and HVP2 in normal HSV-positive control sera (individuals with no known contact with monkeys) are indicated by the dashed line, and average levels of cross-reactivity with the two S. American monkey viruses are indicated by the dotted line. The four sera from monkey forest workers and serum from a fatal case of zoonotic BV infection have higher levels of cross-reactivity with all simian virus antigens than do control sera. (b) Competition ELISAs were performed as described [23, 24] to determine if sera from monkey forest workers with high levels of cross-reactivity were consistent with having been infected with BV. Soluble antigens (extracts of cells infected with HSV1 (blue), BV (red), or uninfected cells (black)) were used to compete the binding of serum to HSV1 antigen coated onto the ELISA plates. Binding of control HSV1-positive serum was inhibited only by soluble HSV1 antigen, not by BV or control antigens. Binding of BV-positive macaque serum (HSV-negative) to the solid phase HSV1 antigen was equally competed by soluble HSV1 and BV antigens. Binding of sera from two patients that died of zoonotic BV infection (both HSV1-positive) were competed by both HSV1 and BV soluble antigens, although competition by BV antigen was less than by HSV1 antigen. Binding competition for sera from two monkey forest workers (both HSV1-positive) was similar to that of zoonotic BV patient sera.